A significant bottleneck in the use of electronic computers and other data processing equipment is the human input interface equipment usually in the form of keyboards. Modern electronic data processors have outstripped the capacities of conventional keyboards by providing capability for handling literally hundreds of control functions and data characters on a single low cost chip. Also any manual input keyboard is sensitive to manual input speed and potential entry errors caused by either equipment characteristics or human error. The need for improved speed, accuracy and high data handling capacity in manual entry keyboards is evident. A further desirable feature is minimal size compatible with portable size computers, which constitute a considerable percentage of the market demand. For small keyboard panels of the prior art there is generally only room for operation by one hand, which further tends to restrict keyboard speed, accuracy and capacity.
Some prior art techniques are proposed to increase keyboard capacity for data processing applications, such as (1) the "chord" system of selection of keys either one or several at a time set forth in U.S. Pat. No. 4,042,777--F. C. Bequaert et al.--Aug. 16, 1977 or German Pat. No. 2924515 -- Jan. 15, 1981, (2) the use of the available keyboard keys in several different modes as set forth in U.S. Pat. No. 3,892,958--C. C. Tung--Jul. 1, 1975 and (3) the use of counted sequential closures of keys a plurality of times to provide a larger number of selections per key as set forth in U.S. Pat. Nos. 4,202,038--S. A. Petersson--May 6, 1980 and 4,272,826--S. Deutsch--Jun. 9, 1981. However, these keyboards all tend to increase the error rate of manual input data by requiring the operator to make mental choices including those which select how many fingers and how many finger strokes are required for an entry. The same is true if a keyboard has a larger number of keys so that an operator's hands get out of register for touch operation, or must have a large reach or hand movement span encompassing a large number of keys.
It is therefore an objective of this invention to improve the manual entry data processor keyboard art by providing structure to reduce errors, improve capacity and increase speed.